1. Field of the Invention
The invention relates to an operating characteristic correcting apparatus capable of stabilizing an operation of an electronic circuit without being adversely influenced by a dispersion of each circuit element due to manufacturing errors etc.
2. Related Art
Conventionally known electronic circuits, such as an amplification circuit amplifying an input signal by a predetermined amplification factor or a constant-voltage circuit converting an input voltage into a predetermined voltage, are generally subjected to undesirable variation in operating characteristics (or performance) due to the dispersion of circuit elements.
According to the prior art, to correct such a dispersion, a predetermined inspection process is provided to check any defect in the operating characteristics of each electronic circuit after the electronic circuit is manufactured. If the operating performance is not satisfactory, the operating parameters of the electronic circuit are modified by adjusting the circuit constant of an adjusting circuit element, such as a variable resistor, provided in the electronic circuit.
However, recent electronic circuits are integrated into a single chip of an IC circuit to facilitate downsizing for shipment. However, executing the above-described adjustment on such an integrated circuit is extremely troublesome.
For example, a power source circuit supplying electric power to an electronic device, such as a microcomputer, may be constituted by an integrated circuit. According to a conventional method, to prevent a deviation of a power voltage produced by this power source circuit, an output voltage of the power source circuit is checked before a manufactured IC substrate incorporating the power source circuit is molded by a resin into a chip component. More specifically, the characteristics of circuit elements of the power source circuit, such as resistors, are adjusted by a laser trimming or fuse trimming method. However, this adjustment is very complicated. Furthermore, if the adjustment fails this chip component becomes defective, thus reducing the overall yield of products.
Furthermore, this kind of electronic circuit is sensitively influenced by the temperature characteristics of circuit elements. Thus, there is a tendency that the operating characteristics will be worsened in accordance with a change in an operating temperature.